1. Field of the Invention
The present invention relates to an internetworking device and method, and more particularly to an internetworking device and method for interconnecting distant networks through dynamically allocated bandwidth resources on a transport network.
2. Description of the Related Art
In recent years, 100 Mbps data transmission technologies (e.g., 100BASE-T Ethernet) are gaining popularity in the field of local area networks (LANs), and the increased LAN speeds make it practical to deliver bandwidth-intensive multimedia data including video and voice information, in addition to transporting computer files. At the same time, the recent advancement of high-performance personal computers (PCs) has enabled general users to enjoy high-speed computing with extremely powerful CPUs and rich memory resources. In the above circumstances, new network applications such as teleconferencing and distance learning have become a reality, taking advantage of LAN interconnect services bridging two or more remote locations. Another typical case of internetworking is an enterprise network system which interconnects distant branch offices and factories by using ISDN services or leased lines. In this system, routers, bridges, or other internetworking devices are used to convert LAN""s physical interface and protocols to those used in an existing telecommunications network, such as 64 Kbps ISDN services.
The above system is, however, unable to provide transparent communication between two distant LANs, because the high bitrate of 100BASE-T LANs has to be reduced eventually to 64 Kbps of the ISDN transport network when one LAN user attempts to communicate with a remote party. That is, the performance of conventional LAN-to-LAN communication is limited by a fixed bandwidth of the transport network being used. Since LAN data traffic is often bursty, the use of a low-speed transport link would result in reduced service quality, including intolerable delay in data delivery. Overwhelming amounts of data bursts could cause buffer overflow, and resultant communication errors would produce additional network traffic for data retransmission.
The above problems of a slow transport network can be solved by employing a leased line with a higher bandwidth, which will enable bursty file transfer traffic to be smoothly transported to the destination network. However, reserving a dedicated high-speed channel to cope with bursty traffic is a costly and inefficient solution, because average LAN traffic is much lower in general than the traffic during peak load conditions.
Meanwhile, asynchronous transmission mode (ATM) technologies may be applied to the transport network interconnecting distant LAN environments. This ATM-based internetworking system, however, may not necessarily be efficient in terms of bandwidth utilization, since ATM cells must carry relatively large overhead information compared to their payload, and adaptation to LAN interface requires another kind of overhead to be added. The network bandwidth consumed by such overhead information cannot be neglected.
As mentioned earlier, existing telecommunications services are normally used to interconnect remote networks and build a wide area network (WAN) environment. However, data communication interfaces provided by such existing services often use complex protocols and need complicated configuration setups, thus imposing more management workloads on the users. That is, the users have to operate and maintain the WAN interface in addition to LANs they are using.
Taking the above into consideration, an object of the present invention is to provide an internetworking device which integrates a LAN interface and an efficient bandwidth allocating mechanism to enable transparent LAN-to-LAN communication.
To accomplish the above object, according to the present invention, there is provided an internetworking device which interconnects at least two distant networks through a transport network. This internetworking device comprises the following elements:
(a) a network interface unit which provides a communication interface to link with each of the networks;
(b) a traffic monitor which monitors data traffic between the networks;
(c) a bandwidth resource database which stores information on bandwidth resources;
(d) a bandwidth allocation controller which dynamically allocates a bandwidth resource(s) sufficient to transport data streams over the transport network, considering the data traffic being monitored by the traffic monitoring unit, as well as consulting the bandwidth resource database; and
(e) a communication controller which controls data transport between the networks through the allocated bandwidth resources.
Another object of the present invention is to provide an internetworking method which employs a more efficient bandwidth allocation algorithm to enable transparent LAN-to-LAN communication.
To accomplish the second object, according to the present invention, there is provided an internetworking method to allow at least two distant networks to communicate through a transport network. This method, comprises the following steps:
(a) providing a communication interface to link with each of the networks;
(b) monitoring data traffic between the networks;
(c) providing a database storing information on bandwidth resources;
(d) dynamically allocating a bandwidth resource sufficient to transport data streams over the transport network, based on the data traffic being monitored and consulting the database; and
(e) controlling data transport between the networks through the allocated bandwidth resources.
The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example.